Explosive



Patented June 4, 1940 UNITE No Drawing. Application October 16, 1939, Serial No. 299,704

Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

The subject of this invention is an explosive. Trinitrophenol or picric acid has long been known to possess favorable explosive properties for use in military shell and bombs, but its use has been restricted because of the fact that it must be loaded by pressing or tamping methods, due to the fact that it is a crystalline compound having a melting point of approximately 122 C. It has been considered unduly hazardous to melt the explosive at the high temperature required so as-to permit it to be loaded by casting. This difficulty has been avoided by adding to picric acid other nitrocompounds to obtain mixtures having melting points considerably below that of picric acid. For this purpose the nitroderivatives of toluol, cresol, the lower nitroderivatives of phenol and of naphthalene have been used to some extent. Certain definite objections were encountered in the use of all mixtures of picric acid with lower nitrocompounds; i. e mono and dinitroderivatives of phenol, cresol, or naphthalene. Mono and dinitrophenol are highly toxic and impart an objectionable toxicity to mixtures of these compounds with picric acid. The mono and dinitroderivatives of cresol and naphthalene were required in such high proportion to obtain liquid mixtures at temperatures below the melting point of picric acid that the resulting explosives were extremely dimcult to detonate and had brisant or shattering effects much below that of picric acid, TNT, or other of the favored high explosives used as charges for shell or bombs.

By experimenting with picric acid and the mono and dinitroderivatives of naphthalene, I have found that high explosives suitable for use in shell and bombs can be prepared free from the objections which have existed heretofore. My improvement in explosive mixtures of this type resides in the fact that I have found it not only unnecessary but distinctly undesirable to add mononitronaphthalene in suflicient amount to picric acid to form liquid mixtures at temperatures of approximately 100 C. If mononitronaphthalene is added to picric acid in an amount sufficient only to provide a liquid vehicle or medium at 100 C. which will carry the crystalline picric acid in suspension and thus permit charging into a shell or bomb, the resulting mixture is highly '=ensitive to detonation and the brisant effects of the explosive mixture comparable to TNT and other acceptable fillers for bomb and shell. This scheme of making the explosive mixtures limits the amount of mononitronaphthalene to 10-15% of the mixture by weight. A lesser amount than will not supply sufficient liquid to carry the crystalline picric acid and permit casting at temperatures obtainable with low pressure steam. While a greater amount than will, of course, provide a more liquid 10 mixture which can be readily cast, such mixtures are sufliciently insensitive and of such low explosive strength that they are not acceptable as shell or bomb charges. The difference in explosive characteristics of mixtures containing 15 10-15% mononitronaphthalene and mixtures containing greater percentages of the mononitrocompound is marked and suflicient to establish the one as practicable and the other as impracticable when the explosives are applied in present day designs of shell and bombs. A further important practical advantage of the picric acidnitronaphthalene mixtures referred to herein is that by restricting as specified the amount of liquid carrier for the crystalline picric acid much less shrinkage occurs upon solidification of the charge in the shell or bomb; this eliminates the objectionable property of all liquid mixtures to shrink upon solidification and thus tend to form porous charges which are likely to detonate prematurely due to setback forces when shells are fired.

Mixtures of picric acid and mononitronaphthalene within the range cited have no objectionable toxicity. They are highly stable as indicated by the 120 C. vacuum stability test in which they give less than 1 c. c. of gas upon heating for forty hours. They can be readily detonated by standard fume and booster systems and have been found to provide fragmentation of high explosive shell closely comparable with that given by TNT and other standard military explosives. Nitronaphthalene and picric acid are both commercially available and when mixtures of these are used as herein specified, they constitute practical substitutes for TNT for use in time of an emergency, if the'supply of TNT should not be sufficient to meet demands.

I claim:

1. An explosive comprising picric acid to 50 and mononitronaphthalene 10% to 15%.

2. An explosive consisting of picric acid 88% and mononitrouaphthalene 12%.

GEORGE C. HALE. 

